Re: [Qemu-devel] [RFC PATCH 14/17] block: support FALLOC_FL_PUNCH_HOLE trimming

[Paolo Bonzini]

Il 09/03/2012 09:35, Chris Wedgwood ha scritto:
>> SEEK_HOLE could provide a very simple heuristic to detect preallocated
>> files (unfortunately ext4 does not implement SEEK_HOLE yet).
> 
> SEEK_HOLE is a weird (confusing and no intuitive) API (IMO).  There is
> FIEMAP or whatever it's called which seems somewhat saner.

FIEMAP is a powertool, we need a butter knife only (cit.).

> Simplest still compare the blocks allocated by the file
> to it's length (ie. stat.st_blocks != stat.st_size>>9).

But yes, you're right about this.

Paolo